Wall scratcher for wells



y 1950 K. A. WRIGHT 2,506,4m5

WALL SCRATCHER FOR WELLS Filed Sept. 25, 1948 2 Sheets-Sheet l KENN7H 7. (Me/6H7,

IN V EN TOR.

May 2, 195 K. A. WRIGHT WALL SCRATCHER FOR WELLS 2 Sheets-Sheet 2 Filed Sept. 25, 19 18 KENNETH n. (Me/6H7 INVENTOR. BY f5 tral portion l of the sleeve I3 and as shown in the drawings this means includes an attachment cli-p generally designated 24. The attachment clip is shaped on its underside 25 to conform to the cylindrical surface 23 and is provided with an axially extending groove 21. These grooves extend into the clip from its undersurface 25. The aligned legs 2| are received within the axial groove 26 and the adjacent feet 22 are received within the circumferential groove 21. The clip 24 is secured to the outer surface 23 of the sleeve l3 by any convenient means, but I prefer to anchor it in this position by spot-welding the clip to the sleeve at the locations indicated by the numeral 28 and shown clearly in Figure 2. Each of the clips 24 is thus anchored to at least three spots and a firm attachment is thereby achieved. The feet 22 which extend at right angles with respect to the legs 2| anchor the ends of the legs 2| against rotary movement about the axis of the legs and the engagement between the axial groove 26 and the legs 2| prevents any other motion of the legs 2| with respect to the sleeve. In this way, relatively rigid attachment is provided for one end of each of the coil springs 20 with respect to the sleeve 3.

Since the scratcher devices |2 may be required to pass through fixed casing in the upper end of the hole as they are being inserted into the well bore they are required to flex inwardly to a very considerable extent and, furthermore, in service prior to and during cementing operations they may be moved vertically or circumferentially or both within the well bore for the purpose of removing the mud sheath and considerable flexing and bending of the shank l8 is therefore required. The coil springs 20 at the inner ends of shanks |8 therefore have considerable movement with respect to sleeve l3 and clearance for this movement is afforded by the aperture Hi. The coil springs are protected against a contact with the sides of the well bore or with fixed casing in the well by means of the ribs M on the sleeve l3 and by reason of the guards or ribs 28 provided on either side of the attachment clips 24.

It is essential that the radial thickness of the scratcher device be maintained at a minimum in order that the pipe I0 and the scratcher devices assembled thereon may pass through fixed casing in the well bore having an inside diameter only slightly larger than the diameter of the pipe Ill. It is also necessary to protect the coil springs 2|! against contact with inside surface of the fixed well casing or with'contact-restricted portions in the open well bore. It will be understood that the embodiment of my present invention meets both of these requirements.

- The attachment clips 24 are shaped so that they may be placed in nested relation on the carrier strip or sleeve l3. Thus the forward nose portion 29 of each clip 24 is adapted to extend into the curved recess 30 provided on the next adjacent attachment clip. Each clip 24 secures a pair of spring fingers H in operative position and no rivets, pins, or other attachment elements are required. Furthermore, no part of the spring fingers extends inside the carrier strip 0r sleeve |3 and hence the annular axial thickness of the device is maintained at a minimum.

As shown in Figure 5, the pairs of spring fingers I! may be mounted on a carrier strip 35 extending longitudinally of the pipe Ill. The strip 35 may be fixed to the pipe by any convenient means, such as, for example, by welding 36. The clips 24 are spot-welded to the carrier strip 34 in the same manner as that described above and the construction of the spring fingers and clips 24 are substantially identical to that set forth above. Apertures 31 may be provided in the carrier strip to provide clearance for the flexing of coil springs 26 at the inner ends of fingers H. A plurality of strips 35 may be mounted on the pipe I0 and may be mounted so that the spring fingers extend in various directions within the well bore. The spring fingers act to remove the mud sheath from the wall of the well bore when the pipe i0 is rotated or reciprocated or both.

As shown in Figure 6, the carrier strip 40 may be formed of two halves connected by hinged joints 4| and 42. The mounting of the spring fingers H on this form of carrier strip 40 is substantially identical to that described in connection with Figures 1-4.

Figures 7 and 8 show a carrier strip 45 shaped as a helix. The carrier strip 45 may be suitably anchored to the well pipe so as by means of welding- 46. The spring fingers i! and their manner of attachment to the helical carrier strip 45 are substantially the same as described in connection with Figures 1-4.

The carrier strips 59, shown in Figures 9 and 10,

preferably extend circumferentially slightly more than one-half revolution. They are sufiiciently resilient to permit them to be moved into position in a radial direction. They are therefore installed after the manner of a spring clip and when once in position remain there without any supplemental holding means while being welded or otherwise secured to the pipe ID. Weld metal 5| may be deposited at intervals as shown. The construction and mounting of the spring fingers H on the carrier strip 59 are identical to that described in connection with Figures 1-4. The carrier strips 50 may be mounted in pairs on the pipe It or may be spaced in any desired pattern along its length.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

1. In a wall scratcher for wells, the combination of a carrier strip adapted to be mounted on a pipe insertable into a well bore, a plurality of wire scratcher fingers mounted on the carrier strip, each of said fingers being formed of a continuous length of wire having one end resting on the outer surface of the carrier strip, said end of each wire comprising an axially extending leg and a circumferentially extending foot, the legs of adjacent fingers being coaxially positioned and their respective feet lying side by side, an attachment clip for securing each pair of adjacent scratcher fingers to the carrier strip, said clip being provided with a first groove for reception of said aligned legs and a second groove for recep tion of said feet, and means for securing each of the clips to the outer surface of the carrier strip.

2. In a wall scratcher for wells, the combination of a carrier strip adapted to be mounted on a pipe insertable into a well bore, the carrier strip comprising at least a portion of a cylinder and having a pair of circumferentially extending radially projecting ribs, a plurality 'of wire scratcher fingers mounted on the carrier strip, each of said fingers being formed of a continuous length of wire having one end resting on the outer surface of the carrier strip, said length of wire being coiled to form a spring at a location intermediate the ends of the wire, the carrier strip having apertures formed therein along the inner edges of said ribs for reception of a portion of said coil springs and to provide clearance for movement of the springs under flexing of the scratcher finger, and securing means for attaching each of said scratcher fingers to said carrier strip including an element secured to the outer surface of the strip between said ribs and overlying a portion of the inner ends of said wires.

3. In a wall scratcher for wells, the combination of a carrier strip adapted to be mounted on a pipe insertable into a well bore, the carrier strip having a plurality of longitudinally spaced, outwardly projecting ribs, wire scratcher means on the carrier strip including attachment means engaging the outer surface of the carrier strip at a region between the ribs and a pair of scratcher fingers each having a portion adjacent said attachment means coiled to form a spring, the carrier strip having apertures formed therein adjacent said ribs for the reception of a portion of the coil springs and to provide clearance for movement of the springs under flexing of the scratcher fingers, and a member secured to the outer surface of the carrier strip between the ribs and overlying the attachment means for mounting the wire scratcher means upon the carrier strip.

4. A wall scratcher for wells as defined in claim 3, in which the mounting member securing the wire scratcher means to the carrier strip is grooved to receive the attachment means of said wire scratcher means.

5. In a wall scratcher for wells, the combination of a carrier strip adapted to be mounted on a pipe insertable into a well bore, the carrier strip having a plurality of radially outwardly projecting ribs formed integrally therewith, a plurality of wire scratcher fingers, each of said fingers having an attachment portion thereof resting on the outer surface of the carrier strip, each wire scratcher finger having a portion adjacent its attachment portion coiled to form a spring, the carrier strip having apertures formed therein adjacent said ribs for the reception of a portion of said coil springs and to provide clearance for movement of the springs under flexing of the scratcher fingers, and securing means for attaching each of said scratcher fingers to said carrier strip including an element secured to the outer surface of the carrier strip between the ribs and overlying said attachment portion of the scratcher fingers.

6. In a wall scratcher for wells, the combination of a carrier strip adapted to be mounted on a pipe insertable into a Well bore, the carrier strip having a plurality of radially outwardly projecting ribs formed integrally therewith, a plurality of wire scratcher fingers, each of said fingers having an attachment portion thereof resting on the outer surface of the carrier strip, the attachment portion comprising an axially extending leg and a foot extending at an angle thereto, each wire scratcher finger having another portion coiled to form a spring, the carrier strip having apertures formed therein along the inner edges of said ribs for the reception of a portion of said coil springs and to provide clearance for movement of the springs under flexing of the scratcher fingers, and securing means for attaching each of said scratcher fingers to said carrier strip including a clip welded to the outer surface of the carrier strip between the ribs, the clipoverlying said attachment portion of the scratcher fingers and being grooved to receive the leg and foot thereof.

7. In a wall scratcher for wells, the combination of a carrier strip adapted to be mounted on a pipe insertable into a well bore, the carrier strip comprising at least a portion of a cylinder and having a pair of circumferentially extending radially outwardly projecting ribs, a plurality of wire scratcher fingers, each of said fingers having an attachment portion thereof resting on the outer surface of the carrier strip between said ribs, each wire scratcher finger having a portion adjacent its attachment portion coiled to form a spring, the carrier strip having apertures formed therein along the inner edges of said ribs for the reception of a portion of said coil springs and to provide clearance for movement of the springs under flexing of the scratcher fingers, and securing means for attaching said scratcher fingers to said carrier strip including an element secured to the outer surface of the carrier strip between the ribs and overlying said attachment portion of the scratcher fingers.

8. In a wall scratcher for wells, the combination of a carrier strip adapted to be mounted on a pipe insertable into a well bore, the carrier strip comprising at least a portion of a cylinder and having a pair of circumferentially extending radially outwardly projecting ribs, a plurality of wire scratcher fingers, each of said fingers having an attachment portion thereof resting on the outer surface of the carrier strip between said ribs, each wire scratcher finger having a portion adjacent its attachment portion coiled to form a spring, the carrier strip having apertures formed therein along the inner edges of said ribs for the reception of a portion of said coil springs and to provide clearance for movement of the springs under flexing of the scratcher fingers, and securing means for attaching each of said scratcher fingers to said carrier strip including a clip welded to the outer surface of the carrier strip between the ribs, the clip overlying said attachment portion of the scratcher fingers and being grooved to receive said attachment portion.

KENNETH A. WRIGHT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

